The invention pertains to a manipulator comprising at least one arm or pivot beam of which one end is articulated on a support machine and of which the other end is equipped with a tool adapted to pivot about the axis of that end of the manipulator, as well as control means such as hydraulic or pneumatic cylinders or motors, cables, chains etc., affording positioning of the manipulator and of the tool.
Conventional manipulators generally require a considerable skill on the part of the machine operator, particularly when the point or edge of the tool must be maintained at a desired level or follow a curve of predetermined shape over a relatively long tool path and preferably over the maximum possible path of the tool.
Known manipulators therefore cannot be operated by an unskilled or semi-skilled worker and do not afford automation of operation.
It is an object of the present invention to alleviate these disadvantages and to provide a manipulator, in particular for public works machine, which can be operated by an unskilled person and affords automation.
This object is attained according to the present invention by a manipulator which comprises two beams of which a first beam, called the command beam is articulated firstly, at its rear end, on a pivot shaft which is fixed to the chassis of a support machine and secondly at its forward end, about the rear end of the second beam, called the follower beam, by means of a common pivot shaft. The forward end of the follower beam is provided with a cradle mounted thereon by means of a pivot shaft. The command beam is made to pivot about its rear pivot axis by means of a rotational or linear motor. Each of the two beams includes a detector means for detecting the pivot angle of the respective beam, a pivot motor provided at the forward end of the beam and adapted to cause the pivoting either of the rear end of the follower beam or of the cradle, as well as transmission means provided between the detector means and the pivot motor of each beam for controlling the pivoting either of the follower beam or of the cradle as a function of the degree of rotation either of the command beam or of the follower beam detected by the detector means of the corresponding beam.
By virtue of the foregoing arrangement an operator need only control the angle of incline of the command beam in order automatically to obtain a predetermined displacement of the cradle on which may be mounted a suitable tool.
The detector means, the pivot motor and the transmission means between the detector means and the pivot motor are advantageously mechanical elements.
In this way the detector means for each of the two beams of the manipulator may comprise a gear mounted on the pivot shaft of the rear end of the beam and stationary in rotation about the axis of that shaft. The pivot motor provided at the forward end of each beam may include another gear coupled to a pivot shaft which is fixed either to the rear end of the follower beam, or to the cradle, and the axis of which coincides with the axis of the pivot shaft either of the rear end of the follower beam or of the cradle respectively. Means linking the detector member (non-rotating gear) and the pivot motor mounted on each beam may comprise either an endless chain, which may be provided with a tensioning device, looped around the non-rotating gear and the gear of the pivot motor, or by a series of intermediate gears comprised of an odd number of gears mounted on the beam by means of shafts parallel to that of the non-rotating gear and engaging one another. In the latter case the rearmost intermediate gear engages the teeth of the non-rotating gear and the forwardmost intermediate gear cooperates with the gear of the corresponding pivot motor.
Advantageously the rear end of the command beam is mounted on the pivot pin of a first yoke or clevis which is fixed to a carriage mounted on a universal joint type support system, itself pivoted on the chassis of the support machine by means of a pivot pin parallel to that of the first yoke, motors or cyclinders being provided between the chassis and the support system, and between the chassis or the support system and the command beam.
The present invention further relates a machine for pre-fracturing lower strata or coatings of pavements treated with hydraulic binders.
In a known method of prefracturing a trough is formed in the lower strata before the final compacting phase, a product is sprayed or projected into the trough and forms a film by solidification in contact with the trough-forming material, and the trough is immediately closed and final compacting effected. The injected product which is preferably a bitumous cationic emultion of low pH and with a relatively high fracture rate, plays a double roll: by its pH aqueuse phase, it creates a low resistance zone which favours the localization of shrinkage cracks and, by its relatively high fracture rate bituminous phase, it creates a discontinuity and affords precise prelocalization of the fracture. The advantages of this method include the precise localization of the fracture, the bituminous treatment of the through faces which become insensitive to water and only slightly sensitive to abrasion, the relatively straightforward execution with negligible effects on the cohesion of the strata and a very low cost per square meter of treated pavement.
A device for carrying out such a method is also known, which comprises means for forming troughs including a V shaped plough type blade which splits the strata, means for projecting a product into the troughs including spray tips or nozzles, and means for refilling the troughs including two inverted V shaped plates.
These three means can be ridgidly mounted on a carriage slideably mounted on a rail corresponding to the width of the road or passage to be treated, and supported on a vehicle which carries a temperature controlled emultion tank and a pump, as well as connecting means for delivering the emulsion to the spray nozzles for projection into the trough. This device is however cumbersome and blocks the entire width of the pavement surface to be treated.
An object of the present invention is to provide an improved prefracturing machine which overcomes the disadvantages of known devices and which is capable of forming narrow troughs in order to limit as much as possible the upsetting of the strata of material already laid down, which does not constitute a permanent obstacle in the area of the strata being treated, which can be perfectly integrated between the other construction phases of a particular project without slowing down the execution of those phases by virtue of an entirely automated work cycle, and which is totally autonomous.
This object is attained according to the invention by a machine for prefacturing the lower strata or coatings of pavement treated with hydraulic binders which includes:
means for forming troughs, PA1 means for projecting a product into the troughs, PA1 means for refilling said troughs, and PA1 means for moving the preceding means during the operation of the machine,
wherein the means for forming troughs includes a substantially vertical, tapered blade of triangular cross section of which the cutting edge is positioned in the direction of movement of the blade during the treatment of the strata; wherein the means for projecting a product into the troughs includes a manifold or spray nozzle fixed to the rear edge of said blade and connected to a holding reservoir for the treatment product by means of a pump; further wherein said means for refilling said troughs includes two scrapers flexibly mounted to the rear of said blade forming a V opening in the advancing direction of the blade; and wherein the blade, the spray manifold and the scrapers, combined to form a single tool, are mounted on the free end of a manipulator such as defined hereinabove.
Said displacement means comprise a support machine including a motor, and on which is mounted a pivoting manipulator operated by said motor and having a free end adapted to be moved horizontally in response to said motor, said blade being mounted at the free end of said manipulator.
The tapered blade affords the slotting of the strata material and the spreading the walls of the trough thus formed to a narrow width, the walls having a natural tendency to close in toward one another immediately after the passage of the blade. The spray manifold, carried by the blade and situated preferably in an open groove at the back of the blade, projects the product onto the material forming the walls of the notch at the moment when the walls close in toward one another. The scrapers fixed to the rear of the blade complete the refilling of the trough and level the upper surface of the treated strata. The scrapers and the treatment product spray manifold constitute along with the tapered blade a tool allowing the formation of a trough, the injection of a product and the refilling and levelling of the trough. Because the blade is fixed to the end of a pivoting manipulator, the width of the area taken up by the machine varies as a function of the progression of the blade, which avoids the machines constituting a prominent obstacle on the surface being treated during treatment.